shoreline, there won't be enough booms or skimmers. we got tired of waiting and we were being told that more booms and skimmers were coming. but we said we can't wait for others, we've got to go out and protect our coast. >> reporter: after i spoke to the governor, i had a chance to go out myself to go on one of the gaps being filled to go on top of the sandbags and get a sense of how well they work. it's working fairly well. it's not fail-safe, it doesn't prevent everything from going through, but it does -- it is fairly effective in stemming most of the tide. and speaking of the tide, that in and of itself is another key factor. the tides often shift around the barrier islands and the gaps will not be fail-safe, but you really got a sense of how ambitious and massive this job is. they've got 40 of these gaps to fill just within these barrier islands, wolf. >> wow, brian todd, he's doing excellent reporting for us from the scene. thank you. how much oil is really spewing into the gulf of mexico? the official estimate has now doubled. one expert says it could be even worse than that. he's standing by to join us